Cassette loading apparatus

ABSTRACT

According to this invention, drive posts (4) secured to a cassette holder (3) serving as a cassette loading apparatus for a VTR, for example, for horizontally holding a cassette slide in slide grooves (14) on arm levers (13) provided at arm gears (11), while abutting on one side thereof. Accordingly, by setting greater the width of the slide groove (14a) formed in the arm lever (13a) on the drive side, the center of the drive post (4a) on the drive side is deviated from the center line of the arm lever (13a). As a result, the drive post (4a) on the drive side and the drive post (4b) on the driven side can be set in phase by setting the phase delay of the arm lever (13b) on the drive side and the phase delay of the drive post on the drive side, which are caused by the backlash of gears including drive gears (18) that engage the arm gears (11) at a front loading time, approximately equal to each other. That is, the phase of the drive post (4a) on the drive side with respect to the drive post (4b) on the driven side can be freely adjusted by properly shaping the slide grooves formed in the arm levers (13). Accordingly, loading and unloading through a front type manipulation can be executed while keeping the right and left ends of the cassette (2) in parallel.

TECHNICAL FIELD

The present invention relates to a cassette loading apparatus for use ina magnetic tape recording/reproducing apparatus, for example, and moreparticularly, to a front loading apparatus for loading a cassette fromthe front side of a video tape recorder (hereinafter referred to asVTR).

BACKGROUND ART

Recently, home VTRs use a front operational type cassette loadingapparatus which loads (inserts) a cassette into a VTR at a predeterminedposition (where a tape is pulled out from the cassette) from the frontside for tape recording/reproducing, and unloads (ejects) the cassetteto the front side of the VTR after its use is finished.

Conventionally, this type of front loading apparatus (hereinafterreferred to as FL) generally has a power mechanism coupled to a cassetteholder for receiving a horizontally loaded cassette. In this case adrive gear is disposed on one side of the cassette holder and a drivengear on the other side. That is, the driven gear interlocks with thedrive gear via a transmission mechanism.

Due to the backlash inevitable to a mechanism using gears, however, theabove conventional FL causes a phase shift in view of the operationaltime between the drive gear and driven gear located at both ends of thecassette holder, at the times of cassette loading and unloading. Thisdeviates the parallelism between the right and left edges of thecassette during operation, so that smooth loading and unloading cannotbe provided.

DISCLOSURE OF THE INVENTION

This invention has been devised to cope with such problem, and aims atproviding an FL type cassette loading apparatus which can eliminate aoperational phase shift between a cassette holder and the right and leftedges of a cassette at the time of loading and unloading the cassette tothereby keep the right and left sides of both the cassette holder andcassette parallel over the entire operational process.

To achieve the above objective, in a front type cassette loadingapparatus comprising a cassette holder for holding a cassettehorizontally, drive posts secured symmetrical at both sides of thecassette holder, a pair of arm gears with arm levers having slidegrooves formed therein for engagement with the drive posts, aninterlocking mechanism for interlocking the arm gears, a drive sourcefor rotationally driving one of the arm gears and a pair of frames,having guide grooves formed therein for engagement with the pair ofdrive posts, the width of the slide groove formed in that of the pair ofarm levers which is located on the drive side is set greater than thewidth of the slide groove formed in the arm lever on the driven side.

BRIEF DESCRIPTION OF THE DRAWINGS

The aforementioned object of this invention and other objects andfeatures will become apparent in the following description of someembodiments given referring to the accompanying drawings in which:

FIGS. 1 through 9 illustrate the basic example of a cassette loadingapparatus according to this invention, FIG. 1 being an externalperspective view of a front loading apparatus,

FIGS. 2 to 5 being a top view, a right side view, a left side view and afront view, respectively, FIGS. 6 and 7 being diagrams, with theessential section taken from the right side view of FIG. 3 andsimplified, for easy explanation of the operation, and

FIGS. 8 and 9 being diagrams, with the essential sections taken from theright side view of FIG. 3 and the left side view of FIG. 4 andsimplified, for easy explanation of the operation;

FIGS. 10 and 11 are side views illustrating the drive side and drivenside of a cassette loading apparatus according to one embodiment of thisinvention;

FIG. 12 is a diagram illustrating the operation of the same embodiment;

FIGS. 13 and 14 are plan views illustrating slide grooves according toother embodiments of this invention; and

FIGS. 15 and 16 are detailed diagrams of the essential sections of FIGS.10 and 11.

BEST MODE OF CARRYING OUT THE INVENTION

First, a description will be given of the basic example of an FL typecassette loading apparatus according to this invention.

This FL type cassette loading apparatus is structured as illustrated inFIGS. 1 through 7. FIG. 1 is an external perspective view, and FIGS. 2to 5 are a top view, a right side view, a left side view and a frontview, respectively. FIGS. 6 and 7 are diagrams, with the essentialsection taken from the right side view of FIG. 3 and simplified, foreasy explanation of the operation.

The following describes only those common in the individual diagrams andessential to this invention.

Referring to the individual diagrams, a cassette holder 3 for loadingand holding a cassette 2 is movably provided between a pair of bodyframes 1a and 1b of a VTR, for example. Drive posts 4a and 4b aresecured to both sides of the cassette holder 3 at symmetrical positions.Guide rollers 5a and 5b are mounted rotatable on these drive posts 4a,4b. The drive posts 4a, 4b are engaged, via guide rollers 5a and 5b,with L-shaped guide grooves 6a and 6b formed symmetrical in a pair ofbody frames 1a and 1b. A loading motor (hereinafter referred to as FLmotor) 7 is secured to one side (1a) of the frame pair 1a, 1b. A wormgear 8 coupled to the drive shaft of this FL motor 7 is engaged with aworm wheel 9 supported rotatable on the frame 1a. A middle gear 10 issecured coaxial on this worm wheel 9, and is engaged with an arm gear11a supported rotatable by the frame 1a. One end of an arm lever 13aprotruding from the arm gear 11a in the radial direction is supportedrotatable on a support shaft 12a of the arm gear 11a. The aforementionedguide roller 5a is engaged in a slide groove 14a formed in the arm gear13a in the radial direction. A pin 15a is embedded in the proximity ofthe base section of the arm lever 13a, and is engaged with a groovesection 16a formed concentrical in the arm gear 11. A pre-load spring17a, which has one end secured to the arm gear 11 a, is engaged at theother end with this pin 15a, so that a pre-load will be given to thecassette holder 3 when the cassette 2 is loaded at a predeterminedposition. An arm gear 11b and an arm lever 13b, having the same relationwith the arm gear 11a and arm lever 13a, are provided on the side of theframe 1b at symmetrical positions. The pair of arm gears 11a and 11bwill have power transmitted by a shaft 19 through drive gears 18a and18b, engaged with the arm gears. FIG. 6 illustrates the state in whichthe cassette 2 is at the initial position where it mounted on thecassette holder 3. FIG. 7 illustrates the state in which the cassetteholder 3 being driven is at the loading position where a tape is pulledfrom the cassette. In this basic example, the slide grooves 14a, 14bformed in the arm levers 13a, 13b have a symmetrical shape.

The operation of the FL constructed as above will be described referringto FIGS. 6, 8 and 9. As shown in FIG. 6, the rotation of the FL motor 7is transmitted to the arm gear 11a on the driven side through the wormgear 8, worm wheel 9 and middle gear 10. This rotation of the arm gear11a is transmitted to the arm lever 13a by making the pin 15a embeddedin the arm lever 13a abut on one end of the groove section 16a formed inthe arm gear 11a. Further, the drive post 4a secured to the cassetteholder 3 is moved in the direction of the arrow D via the guide roller5a engaging the slide groove 14a formed in the arm lever 13 and isguided along the guide groove 6a, thereby moving the cassette holder 3in the direction of the arrow D. Meanwhile, power is transmitted to thearm gear 11b on the driven side shown in FIG. 9 through the drive gear18a engaged with the arm gear 11a on the drive side, the shaft 19 andthe drive gear 18b engaged with the arm gear 11b on the driven side, andthe cassette holder 3 will be moved in the same manner.

If the improvement of this invention as described later is not made insuch an operation, however, there exists a backlash between the armgears 11a, 11b and drive gears 18a, 18b on the drive and driven sides.This causes a phase shift between the center lines A--A and B--Brespectively connecting the centers of the right and left arm gears 11a,11b to the drive posts 4a and 4b. Since the pair of guide rollers 5a, 5bmove approximately on the center lines A--A and B--B, respectively, theguide roller 5b on the driven side always moves later than the guideroller 5a on the drive side at the operation time even if the centerlines A--A and B--B are first set in phase.

In order to provide the parallelism of the right and left of thecassette when unloading it, the center line B--B on the driven sideshould be shifted with respect to the center line A--A on the drive sidein the cassette unloading direction indicated by the arrow E by thebacklash of the aforementioned two pairs of gears 11a, 18a and 11b and18b. In this case, however, the center line B--B will be further delayedat the time of loading the cassette as indicated by the arrow D, ascompared with the case where the center lines A--A and B--B are set inphase, and the right and left unbalance tends to increase at the timethe cassette is set down or mounted with pressure. On the other hand, tomatch the phase in the cassette down operation and cassette mountingwith pressure at the time the cassette is loaded, the center line B--Bshould be shifted in the direction of the arrow D with respect to thecenter line A--A by the backlash. In this case the parallelism of theright and left of the cassette is deteriorated at the time of unloadingthe cassette as indicated by the arrow E.

As described above, according to the FL of the basic example, when thepair of arm gears are rotated interlockingly via the drive gears and thecassette holder is moved by the arm levers that rotate together with thearm gears, the center lines of the pair of arm levers do not coincidewith each other due to the backlash caused by the engagement of the armgears with the drive gears. Further, if adjustment is made to set thecenter lines in phase at the time of loading or unloading the cassette,the phase shift will become greater at the time of the reverseoperation.

Referring to the diagrams, a description will now be given of an FL typecassette loading apparatus according to one embodiment of this inventionwhich solves the above problems.

FIGS. 10 and 11 are side views illustrating in contrast the drive sideand driven side of one embodiment of this invention. In these diagrams,the same reference numerals are given to identical or equivalentsections of the basic example shown in FIGS. 1 through 7 and FIGS. 8 and9, thereby omitting their description. The feature of this embodimentlies in the shapes of slide grooves 14a and 14b formed in the arm levers13a and 13b, and the other sections are the same as those of the basicexample. The width Wa of the slide groove 14a formed in the arm lever13a on the drive side shown in FIG. 10 is greater than the width Wb ofthe slide groove 14b formed in the arm lever 13b on the driven side. Thewidth Wb of the slide groove 14b on the driven side is nearly equal tothe diameter of the guide roller 5b, and the width Wa of the slidegroove 14a is formed in such a way as to make the amount of the phaseshift of the guide rollers 5a, 5b, caused by the backlash resulting fromthe engagement of the gears 11a, 18a and 11b, 18b, equal to (Wa-Wb).

The operation of the present embodiment will be described referring toFIG. 12. As the guide roller 5b on the driven side is engaged almostwithout a gap, with the slide groove 14b formed in the arm lever 13b onthe driven side, the phase of the guide roller 5b always coincides withthe center line B--B of the arm lever 13b. Assume that the guide rollers5a, 5b move in the sequence of P₁ →P₂ →P₃ →P₄ →P₅ →P₆ →P₇ →P₈ betweenthe positions P₁ and P₈ where the cassette 2 is mounted to and detachedfrom the cassette holder 3, the loading positions P₄ and P₅ where thetape is pulled out from the cassette, and the middle positions P₂, P₃,P₆ and P₇ there between. In the operation at P₁, since the guide rollers5a, 5b are pushed by a hand, the right and left have the same phase. Inthe operation at P₂, the center line B--B of the arm lever 13b on thedriven side will have a phase delay with respect to the center line A--Aof the arm lever 13a on the drive side. Since the guide roller 5a isalso at the phase delay position with respect to the center line A--A ofthe arm lever 13a, however, the center line A--A coincides with thecenter line B--B of the arm lever 13b on the driven side. The sameapplies to the operations at the positions P₃ to P₇. In the operation atP₈, the guide roller 5a on the drive side tends to be slightlyadvancing; however, this does not raise any problem in consideration ofthe safety of the cassette holder in slot out status.

According to this embodiment, the feeding phase shift of the right andleft sides of the cassette holder resulting from the backlash betweentwo pairs of gears 11a, 18a and 11b, 18b can be eliminated and theparallelism of the cassette at the slot out time of the cassette can bemade equal to the pressure on the right and left of the cassette at theslot down time.

FIGS. 13 and 14 illustrate other embodiments of this invention.According to the embodiment shown in FIG. 13, that portion, indicated bythe slant lines, of the peripheral side of a slide groove 14a formed inthe arm lever 13a on the drive side on which the guide roller 5a abutsat the unloading time is removed. According to this embodiment, sincethe phase delay of the guide roller 5a occurs in the operation at theposition P₈ in FIG. 12, the phase shift can be eliminated.

According to the embodiment shown in FIG. 14, that portion, indicated bythe slant lines, of the peripheral side of a slide groove 14a formed inthe arm lever 13a on the drive side on which the guide roller 5a abutsat the loading time is removed. According to this embodiment, it ispossible to eliminate the phase shift caused in a case where thecassette 2 is driven from the beginning at the position P₁ in FIG. 13.

Although the foregoing description has been given with reference to thearm gear 11a on the drive side being directly engaged with the drivegear 18a, the engagement is actually made via an intermediate gear 20 asshown in FIG. 15. The arm gear 11a on the drive side has a smallerdiameter than the arm gear 11b on the driven side shown in FIG. 16 bythe intervention of the intermediate gear 20. These contribute toproviding synchronization of the right and left ends of the cassetteholder 3.

As describe above, according to this invention, since the width of thedrive side slide groove, one of two which are formed in a pair of armlevers for driving a cassette holder and engaged with drive postssecured to the cassette holder, is set greater than that of the drivenside slide groove, the phase shift of the right and left of the cassetteholder caused by the backlash of the gears that interlockingly drive thepair of arm levers can be eliminated, the cassette holder and cassettecan be held in parallel over the entire operational process, and thecassette mounting pressures on the right and left of the cassette at thetime of mounting it can be made uniform.

INDUSTRIAL APPLICABILITY

This invention can be utilized in a system for loading a cassette byfront operation, and is particularly suitable as a front loadingapparatus in a VTR.

I claim:
 1. A cassette loading apparatus comprising:a cassette holderfor holding a cassette horizontally, said holder having at least twoside supports; a pair of first and second drive posts, having a pair offirst and second guide rollers each of a predetermined size, andprovided on one of said at least two side supports of said cassetteholder; a pair of first and second arm levers, said first arm leverhaving a first slide groove formed therein, said first slide grooveengaging said first guide roller, said second arm lever having a secondslide groove formed therein, said second slide groove engaging saidsecond guide roller; a pair of first and second arm gears, said firstarm gear being provided integral with said first arm lever, said secondarm gear being provided integral with said second arm lever; a drivemechanism for driving said first arm gear so as to cause it to rotate; atransmission mechanism, provided between said first and second armgears, for transmitting rotation of said first arm gear to said secondarm gear; and a pair of first and second frames, said first frame havinga first guide groove formed therein, said first guide groove engagingsaid first guide roller, said second frame having a second guide grooveformed therein, said second guide groove engaging said second guideroller, each of said first and second guide grooves having aconfiguration that allows the cassette cassette mounted position and acassette detached position; and wherein each of said first and secondslide grooves has, at a position corresponding to said cassette mountedand detached positions, a width allowing said first and second guiderollers to have the same phase, and said first slide groove has, at aposition other than said position corresponding to said cassette mountedand detached positions, a width greater than that of said second slidegroove.
 2. A cassette loading apparatus according to claim 1, wherein apart of that portion of said first slide groove which has the widthallowing the same phase to said first and second guide rollers isremoved at a region where said first slide groove and said first guideroller are in contact with each other when the cassette is located atsaid cassette detached position.
 3. A cassette loading apparatusaccording to claim 1, wherein a part of said that portion of said firstslide groove which has the width allowing the same phase to said firstand second guide rollers is removed at a region where said first slidegroove and said first guide roller are in contact with each other whenthe cassette is located at said cassette mounted position.